Thursday, October 02, 2008

Interbike - TT Bikes

Two nights ago I had a dream. Normally I don't dream (or technically remember my dreams), so when I realized I was (not really) taking off from Las Vegas again, a clear view of the ground below me, I decided it was okay. There was something odd though, something not quite right, and when we got over Red Rock Canyon, the plane heeled over to the left.

I had that feeling in my gut of "I'm about to crash", but I realized that, if this was real, it'd be a long few minutes before we hit.

Suffice it to say that I didn't get back to sleep for more than two hours. I spent a good part of that time thinking of ways to survive such an incident. If, one day, you're walking in the airport and you see a little concession stand that is selling "Plane Failure Survival Kits" then you'll know who's behind it.

The missus, incidentally, thought that sales wouldn't go too well.

Anyway, because of this extreme lack of sleep, I hadn't even thought about uploading pictures. And now that I have, I'm amazed at how much better our DSL is compared to the wireless broadband. Instead of 10 minutes for 5 pictures, it's more like 20 or 30 seconds.

So, get ready for a picture rich post. The topic today? Time Trial bikes.

TT bikes have a special place in my heart. As a kid in high school I followed the 84 Olympic team's quest for a perfect time trial bike. They ended up with some of the fastest bikes out there - small 24" wheels for team events (better drafting), full size rear wheels for solo events, tension disk wheels, super narrow hubs and bottom brackets, and some beautious frames and forks.

I drew pictures of time trial bikes everywhere - notebooks, margins, back of tests, anywhere I had a blank expanse of paper and a pencil. Or, if I was daring, a pen.

However, for all that time trial bike lusting, I can't time trial well. I had a nice time trial bike for a while - a 24"/700c Nishiki, double UNI disk wheels, and later a prototype rear disc wheel with a 24H M17 front wheel with a 17 mm Panaracer tire. I went from bull horns to the 100k Lemond bars, I had the saddle slammed forward, even went to a 54T big ring.

It got me a 16:28 on a 7 mile course.

My then leadout man did a Merckx style 15:55 - 32 spoke wheels, not even aero brake cables. A national class triathlete did a 14:05, whomping the best USCF rider's time of 15:05 (a Cat 1 or 2, depending on the year, and a phenomenally fast racer).

Ultimately, regardless of my steed, my time trialing sucks.

So why the fascination with time trial bikes?

Because they represent the cutting edge of bikes. The fastest, bestest things to go in a straight line. It's like my fascination with F1 cars - I won't drive them but I'm still enthralled by them if I see a display or a plastic model or even a picture of one in an unexpected place (an ING ad, for example).

Time trial bikes, while totally cutting edge, seem to be converging into a certain design combination, sort of like aero wheels. Nowadays, if you want a fast wheel, you have a tall rim, 16-20 spokes, and a wider than narrow rim (to make the tire a part of the aero profile). They all seem to have the same checklist - right now it includes a rearward mounted front brake, cables diving into the top tube, a downtube that fairs the front wheel and fork, a head tube that is either bulbed or faired or sits behind a blade type steerer tube, a faired in rear wheel, an aero seat tube thing, and finally some aero seat stays.

I looked at the Fuji, Scott, and Cervelo earlier. They actually surprised me with some of their radical (but within the rules) ideas. There were four more that caught my eye, enough so that I snapped a bunch of pictures.

First up, the Argon 18. I always want to say "Aragorn", and then "Leaves are falling all around", but that's me and the hobbit talking.

The bull-like stance fo the Argon 18 TT bike.

Incredibly this is the only blade type fork in this post.

I thought for sure BMC would be showing something, ditto Giant, but alas, the "fork in front of the headtube" thing seems to be less stylish than I thought. Perhaps there isn't any tangible aero benefit with the design, or perhaps it costs too much. I think it would make it much easier to stick a brake on the backside of the fork - the steerer tube is in front of the headtube, freeing up that critical area just under the lower headset bearings, but maybe it doesn't work that way. Regardless, the Argon 18 is the only one with it.

What a smooth front end - no brake, no fork-headtube junction, just a long two-prong fork.

This looks a little more traditional. They must be pushing the limits of the UCI rules, like the Fuji mentioned before.

Curiously enough they had the same side pull U-brake in the rear. I wonder if it would be simpler to have a standard brake back there.

The chainstays are beefy. TT bikes can emphasize these since they don't hit a lot of virgin air.

Alphabetically the Jamis is next. The local guys sell this bike, and I have to admit that it checks off almost all the boxes.

This bike has almost everything checked off on the "TT bike checklist". The rear wheel is not as aggressively faired as other bikes.

One of the things on the checklist - front brake behind the fork.

Although blurry, this show shows the sacrifice made to hide the brake - a flared out fork. I don't know if it's significant, but it's the widest fork I've seen. Does that disrupt airflow onto the downtube? The other notable thing is the waisted head tube.

Another - cables into the frame behind the stem.

I like this post because it looks and smells integrated but it has the convenience of a normal post. Note the slim seat stay yoke - is that more aero? No brake up there so nothing to disrupt air flow.

Another checklist item - hidden rear brake, in this case behind the BB.

I'm curious about the Jamis because it's probably the only bike listed here that I'll be able to test ride. I can't imagine being good enough that the few watts it saves becomes significant but if I can ride one around that'll be fun.

Next up, the Ridley. I have a fascination with this bike because it has the double fork and double stays, something that may give a boost to aero slickness by preventing the spinning wheel and tire from forcing air up and forward.

The very tough looking Ridley, helped by the awesome posters behind it.

Wow. Is this legal? Must be, raced it in the Tour. I'd think a blade type fork would be better.

A look at the back of the fork. Simple, effective.

A look at the RFlow double fork blades.


As you move to the rear, you can see the wide BB area and the under-BB mounted rear brake.

With clearances like this, you won't need a tire saver.

The rear RFlow double seat stays. Although the rear stays are in pretty disrupted air, the RFlow helps with air flowing backwards relative to the motion of the bike. So it may still help, but I imagine the benefit to be less significant.

Cadel Evans is the one that laid it on the line in the final time trial of this year's Tour. Although he was up against what seemed to be vulnerable opponents, he faded hard. If he'd won, this bike would be talk of the town. Since he lost, well, nothing compelling to check out here. But, if the data for the RFlow pans out, there's something there, at least for the fork (i.e. up at the front). I wonder if that's one reason why they put the weird headtube thing on this frame - so you can't easily fit the fork onto, say, a Jamis.

Specialized has the Transition. Gerolsteiner, sponsored by the big S, had their top riders sit on a different TT bike. I wonder what SaxoBank will ride in the 2010 time trials. If they ride Transitions, it will be a huge coup for Specialized. If not, this bike will languish in the stores.

Specialized goes with a front brake mounted in front of the fork.

The humpbacked top tube seems ripe for a specially shaped stem to fill that big gap. Of course, with the disrupted air flow back there, it might be that the gap serves a purpose. The frame does have a pretty aggressively faired downtube, smoothing out the fork crown to frame turbulence.

The very aero looking front brake. The aluminum caps make for a nice look.

The signature bit of the frame - the zig zagging seat tube.

Vertical is better than horizontal, because vertical (aero) tubes present less surface area for air to pass over. Having a downtube is about the worst thing for a TT bike - that's why the Lotus didn't have one. With the UCI's rules about diamond framed bikes, all TT bikes have to have a downtube. The seat tube, though, seems to get more and more crooked. If the tube cross section doesn't violate the UCI's 3:1 length:width ratio, you're okay. But if you want to fair the rear tire, you have to arc that 3:1 ratio, and ideally the seat post (or tube) should be vertical up to the seat. Hence all the zig zagging.

The bottom bracket - wide and stiff looking. The rear brake is behind the BB.

I squeezed the rear stay of the frame after watching a friend of mine do that. The tubes are very, very thin.

The Wilier is the last up in this four bike story. This bike was designed with the help of John Cobb in 2006. Seems old, right?

I think this bike looks wicked.

An extremely waisted headtube, with a little air poking lump at the front.

The fork looks like the wet molds got pulled back in a high speed wind tunnel. That area behind the stem is screaming for cable insertion - and a faired in stem.

Only the front mounted brake and the standard cable routing dates this frame. If redone now I think the brake would be hidden and the cables poked into the top tube. And it would look a lot like the Specialized.

I'd buy the frame just so I could look down and see this.

I'd love to ride this bike in the rain. I wonder if the spray coming off the tire would simply fly onto the frame. If I had a little wick at the end of that downtube pimple maybe the water would just stream past the downtube instead of splashing onto my legs. It's fascinating to me that the lump is so low compared to, say, the Felt.

The seat tube fairs the rear wheel well.

Okay, with those four, I've covered the TT bikes that caught my eye. I missed one that was extreme (UCI illegal) but I still pine to have the talent to justify such a bike.

Until then I'll just look at pictures.

3 comments:

casual entropy said...

i have a hard time getting too excited about modern time trial bikes - they're really getting into intense level of details and I have a hard time staying engaged. However, I get all breathless thinking of the rapid pace of aerodynamic developments - both successful and unsuccessful - happening in the 80s. I really enjoy finding time trial videos on youtube and seeing who is using what gear - helmets, wheels, frame geometries and team tactics. At that point, it seems, everybody was busy divining what strange-looking changes would have the most effect. the developments were so dramatic and happening so fast. I love knowing that Lemond might not have won tdf in '89 if Fignon had worn a helmet.

also, i'm starting a new blog - more focused, better writing, and possibly to work in conjunction with a radio show that is in the very early stages of development. nooneline.blogspot.com - check it out!

-CE

Aki said...

I too enjoyed the 80s and early 90s. It got a bit weird with the Pinarellos under Riis/Ullrich, but the Looks, oh man I loved the Looks. I remember all the various articles (and I saved many of them) about the technical/time differences between the various riders, esp in the 89 final TT.

The diamond frame rule I think was good though, keeping things within a framework. It's like F1 - cutting edge, but with limits. The frames were too crazy coming up to that.

Good luck with the radio show and have a good time with the blog. It's hard work at times but with a passion like this, it's hard to let it down.

casual entropy said...

are you talking about these Pinarellos? I agree that the diamond-frame requirement is a good one. There has to be a line drawn between bicycles and other human-powered vehicles. It's bound to be arbitrary, but it has to be there.

It was too bad the way that every time Graemme O'bree did something according to rules in place, the UCI changed the rules in order to keep up. But that conflict, too - between one person's very rapid innovations and the emergence of rules designed to say, "Okay, woah, we have to hold on here" - was bound to happen.